Very minor issue:
When hitting a window-controlling hotkey (like Esc) with the card browser in focus, but while a child-window (like the HTML editor or Preview) is open, the action is not executed immediately but instead postponed until that subwindow is closed.
I guess the expected behavior would be to either discarded the key or pass it to the sub-window.
[It’s kind of an grievance to me since I’ve several dozen times so managed to accidentally have the wrong focus and kill the browser instead.]